Application of Geophysical Methods in Urban Infrastructure Management in Lagos State

This study examines the professional application of near-surface geophysical methods in urban infrastructure management in Lagos State, South West Nigeria. Lagos State faces increasing challenges in managing ageing underground utilities, groundwater resources, and foundation conditions for ongoing urban development, and geophysical methods offer non-invasive solutions to subsurface characterisation challenges that conventional civil engineering approaches address inadequately. This study reviews the deployment and outcomes of geophysical surveys conducted for infrastructure management purposes in Lagos State over the period 2019 to 2023, drawing on project reports, procurement records, and technical reports from Lagos State Public Works Corporation, Lagos Water Corporation, and selected engineering firms. Survey types reviewed include GPR for utility mapping, ERT for foundation assessment, borehole geophysics for water supply management, and seismic HVSR for building site characterisation. Survey outcomes are assessed for technical quality and decision-making utility. Findings reveal increasing adoption of GPR for utility mapping in road rehabilitation projects, with 24 utility detection surveys conducted between 2019 and 2023. However, survey quality is variable, with a significant proportion of reports lacking adequate processing documentation or quality control. Geophysical capacity within the public infrastructure agencies is limited, with procurement of geophysical services dominated by external consultants with minimal in-house competence for result review. The study concludes that the institutional framework for integrating geophysical methods in Lagos urban infrastructure management requires strengthening. It recommends mandatory technical standards for urban geophysical surveys and in-house capacity building within key public agencies.

Keywords: urban infrastructure, geophysics, Lagos State, utility mapping, capacity building.